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Bipbip

macrumors newbie
Original poster
Jan 30, 2024
6
4
Hello everyone,

I'm having issues with my Apple Watch Ultra 2, mainly losing heart rate data during exercises.
Sometimes I lose pace and power data, but much less often.
These data losses are very variable, from the beginning, middle or end of exercise, over durations ranging from a few seconds to several minutes.
I also get erroneous curves (e.g. Run2) where the heart rate rises sharply at the start of exercise, then falls back to something much more normal.
I'm attaching screenshots of the curves I get after a workout, curves obtained with Healtfit, to explain what I mean.
I'd also like to point out that on races, heart rate readings are good, but this is still too rare.

I've tried everything, loosening and tightening the strap I wear far from the wrist bone.
The watch is always clean.
Unlocked, reset as new watch.
I contacted AppleCare, who found nothing after diagnosing the watch.
I went to the Apple Store, to have a Genius check the data loss, who discovered that he too had this kind of missing data with his Apple Watch Ultra 2.
The latest solution proposed by Apple is to send the watch back to be checked.
Unfortunately, parting with the watch is problematic given that I'm in the middle of my training, I need it for my workouts and splits etc. I'm a bit lost and at a loss.

I'm at a loss, so I've come to ask you if you've come across this kind of bug, which annoys me greatly, given the price of the device, the on-board components and what it's designed for.

I hope to hear from the community, thank you in advance.
 

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renaultf1

macrumors newbie
Jan 7, 2010
24
9
I had the same thing happen. For me I was walking outside in really cold weather and it would constantly drop. I found a few articles that suggested it could be how my body handles the cold and that a wrist reading could cause problems. It suggested a heart rate chest strap. So I bought a Polar H10 and have not had the problem since. If you have a chest strap, you might want to sync it to your watch (not your phone) and see if that works.
 

Howard2k

macrumors 603
Mar 10, 2016
5,286
5,123
It's normal for it to happen in cold weather. Wearing long sleeves and gloves may help. Or a strap like the H10. I wonder if the H9 would be a good option too?
 

Bipbip

macrumors newbie
Original poster
Jan 30, 2024
6
4
Merci for your feedback @renaultf1.

It happens whatever the weather, hot or cold.
It even happens when I workout indoors (picture 6/7 is an indoor rowing exercise).

I'd buy a heart rate monitor if I wanted to get more accurate readings, not to solve a problem of poor readings from the watch, the AWU2 should be almost infallible on heart rate capture.

Also, I wore a heart rate belt for many years with my Garmin Forerunner and always found it unpleasant to wear.

Do you have an AWU2?
Have you only noticed this in cold weather, never in moderate or hot weather?
 
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renaultf1

macrumors newbie
Jan 7, 2010
24
9
Merci for your feedback @renaultf1.

It happens whatever the weather, hot or cold.
It even happens when I workout indoors (picture 6/7 is an indoor rowing exercise).

I'd buy a heart rate monitor if I wanted to get more accurate readings, not to solve a problem of poor readings from the watch, the AWU2 should be almost infallible on heart rate capture.

Also, I wore a heart rate belt for many years with my Garmin Forerunner and always found it unpleasant to wear.

Do you have an AWU2?
Have you only noticed this in cold weather, never in moderate or hot weather?
Yes, I have an AWU2 and it only happened to me in cold weather...the watch alone worked great right up until really cold winter. Wasn't thrilled about going back to having to wear the heart rate monitor, but it does solve the problem. At least I only need to wear it in the winter - seemed to start in anything under 20F. I live in Maine, so at this point, I just need it to work...and it does.
 

juhap88

macrumors newbie
Nov 1, 2022
6
0
I noticed hr data drop too in cold weather. I'm pretty sure gen 1 ultra didn't have this issue?
 

Bipbip

macrumors newbie
Original poster
Jan 30, 2024
6
4
I train almost every day and very rarely have a session without data loss.
Today I went to the gym, here are a few screenshots, in order of the session.
First screenshot, elliptical trainer, followed by rowing machine, then a screenshot of an abs, pecs and back workout.
The conditions under which the watch was worn were exactly the same for each exercise.
It's really not what I expected when I bought this watch.😞
 

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Jackbequickly

macrumors 68030
Aug 6, 2022
2,515
2,577
Everyone of my Apple Watches have had drop out in HR data. Does not happen often but maybe 1 in 10 workouts. .
 
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BillGates1969

macrumors 68000
Sep 11, 2008
1,730
3,518
Poole, UK
I have an AWU2 & S7, just upgraded the U2 from an U1.

My U1 never (well practically never) lost the HR reading during my daily Fitness+ workouts, though the S7 did occasionally. My U2 loses it about 2-3 times for about 30 seconds every day in a 20 min workout. Tried different straps, tighter on the loops etc, but still loses it. Really weird as my U1 was rock solid.
 

Jackbequickly

macrumors 68030
Aug 6, 2022
2,515
2,577
Interesting @Jackbequickly.
And what about your Apple Watch Ultra 2 ?

‘It is no different that my previous Apple Watches. Sometimes it loses the HR and need to be adjust a bit on the wrist. Like I said, it does not happen often but it does happen. When starting on a workout, I usually check a few times to make sure it is reading HR. I tend to wear my AW loose until I start a workout, at which time I tighten it a bit.
 
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Bipbip

macrumors newbie
Original poster
Jan 30, 2024
6
4
@BillGates1969 It's very similar to what I encounter.
@Jackbequickly When I start a session, the cardio functions correctly - in any case, the display shows the heart rate and it evolves correctly. It's really during the session that the cardio is lost.
Before, sometimes on the watch, the cardio is grayed out and doesn't change, but other times, most of the time, I frequently look at the watch, nothing abnormal on the display, but on arrival, on the graphs, it's a disaster.

I'm trying to understand why, for some people, everything seems to work almost perfectly and for others it's catastrophic.

Is it a problem of technology that remains bad when used on the wrist, yet some people seem to have no problems or much less than what I describe.
Is it a morphological problem, the sensor doesn't work as well when the wrist is thin, with little fat, which could explain why some people get better readings than others.
Is it that Apple uses different components for the heart rate sensor, as they do for other iPhone components for example, and that some of these models perform less well.

I've opened other posts on different forums and other users are experiencing this problem.
Apple should clarify this and explain why the results are different for different users, the watch is the same price for everyone but the quality is not the same for everyone. This is not normal.
 
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Howard2k

macrumors 603
Mar 10, 2016
5,286
5,123
However, some users have not complained and have not noticed any particular problems with cardiac capture.
Losing some data may be tolerable, but not capturing half of a 15-kilometers run is a major flaw.

I know, I'm not saying that losing 15km is normal, I'm just saying that all optical wrist based heart sensors struggle in cold weather.
 

renaultf1

macrumors newbie
Jan 7, 2010
24
9
I noticed hr data drop too in cold weather. I'm pretty sure gen 1 ultra didn't have this issue?
I had a gen 1 ultra before my AWU2 and mine dropped data in the cold - so not just a AWU2 issue. I got the HR strap when I had the Ultra gen 1.
 

mtbdudex

macrumors 68030
Aug 28, 2007
2,701
4,294
SE Michigan
Timely topic, I was going to post same and see you did.
I’ve had my AWU2 since December 2023, and have noticed quirks with it on HR data. Posted a few screen shots below.

e334e021f4f334293df27655f999b702.jpg

dd4d772c588740731843246ea4fdcbe4.jpg

159490c17e618f898eae34875be89a12.jpg


Here’s it on my left wrist, I’m guessing it’s related to the bone and making sure it’s snug just behind it not on it.
Behind
af20595a5aac7f46b72b665b8f1591ed.jpg

On
4289c271cace029a8c75b96cbe52c20a.jpg


Yea, that bone
85e5a2c6ac4d54ac0becb1e5711e3a0b.jpg


Before the AWU2 I had an Apple Watch 7 a few years and after 100’s uses near zero HR drops.
Possibly the larger back size of the AWU2 vs std Apple Watch makes some intermittent contact issue more?

I don’t feel it’s cold related, at least for me. It’s worked fine on near zero deg f days as seen here in January. Yes it’s on my wrist, then below 2 layers of merino wool and thin top layer.
f3a5e6c6296d8f090d0a2ff0e34a8f71.jpg
 
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mtbdudex

macrumors 68030
Aug 28, 2007
2,701
4,294
SE Michigan
Well I posted this in my local MMBA facebook group. One person suggested to wear the watch inside of wrist to avoid the bone.
Hmm, I like that idea.

I just tried it, but the crown and other button might get pressed on wrist flex now.
a8dea07268667389c6ab3f4362997b23.jpg


So, I turned it so crown is now on other side. Since this is a temporary “MTB ride the watch “ thing I won’t rotate the display in watch settings, as normally it’s on the topside.
04ce673acc841c0998fcb08ae368f84e.jpg


Will try it out tomorrow’s ride.
Crossing fingers.

Edit - 10 seconds to do this .. ha
d2ee97f24e78ec46c3b3b7f817dee604.jpg

656f35e03bbd8d1be31d16239c2af72b.jpg


^^^
My concern is scratching the watch face if worn 24/7 on inside.
 
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mtbdudex

macrumors 68030
Aug 28, 2007
2,701
4,294
SE Michigan
Btw, in that facebook post even though the very first sentence I posted was;

Please no “use a chest strap for HR”, TIA

Of course a few spews “use a chest strap”

To which I then replied:

I did use a polar watch / chest strap combo late 1990’s / early 2000’s when I raced competitively.
Ha, I really did live to race, single no kids raced every weekend, rode 4 days a week plus race weekends.
Now, I’m past that and just using the watch as a data gathering tool.

Here’s a good article on the Ultra watch and its HR accuracy

 

mtbdudex

macrumors 68030
Aug 28, 2007
2,701
4,294
SE Michigan
However, some users have not complained and have not noticed any particular problems with cardiac capture.
Losing some data may be tolerable, but not capturing half of a 15-kilometers run is a major flaw.

As the OP did you “solve” this issue?
Or find ways to mitigate it?
TIA,
Mike R
 
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